I was walking my dog after getting home from a late class. It was after 11 pm CST but not yet 11:30. My dog was lingering in a parking lot so I looked up as I often do to observe the stars. I saw what I thought was a plane taking off from Love field, north of Dallas, without its bright landing lights on. I thought that was strange because I expected the dimmer lights to be red and green for port and starboard. The lights were square, orange and made a perfect triangle. The craft never made any noise at all! It moved in a straight line over downtown Dallas at an almost due south direction; slightly east. I watched for 20 minutes for other crafts or for it to return and saw nothing. It was relatively larger than the little dipper which was also visible.